BACE1 Inhibitory Activity Research Articles

Chinese Prescription Kangen-karyu as Potential Anti-Alzheimer’s Disease Therapeutic: Analyses of BACE1 and GSK-3b Inhibitory Activities

Inhibition of β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) or glycogen synthase kinase-3β (GSK-3β) is estimated to be the central therapeutic approach for Alzheimer’s disease (AD). In this study, water extract of Kangenkaryu, its crude drug and chemical composition used in oriental medicine were evaluated regarding their BACE1 and GSK-3β inhibitory activities.Fluorescence resonance energy transfer was used to characterize the BACE1 inhibitory effect of Kangen-karyu, its crude drug and chemical composition.GSK-3β activity was determined using the Kinase-Glo Luminescent Kinase Assay Platform. The water extract of Kangen-karyu inhibited BACE1 and GSK-3β in concentration-dependent manners when compared with reference drugs, quercetin and luteolin. Among six components of Kangen-karyu, the water extracts of Salviae Miltiorrhizae Radix or Cyperi Rhizoma exhibited significant inhibitory effects on BACE1 and GSK-3β. Among the constituents of Salviae Miltiorrhizae Radix extract, salvianolic acid C, salvianolic acid A, rosmarinic acid, and magnesium lithospermate B significantly inhibited BACE1. In addition, they inhibited GSK-3β with an IC50 value range of 6.97 to 135.35 μM. From these results, one of the effectiveness and its mechanisms of action of Kangen-karyu against AD may be the inhibition of BACE1 and GSK-3β, and one of the active ingredients of Kangen-karyu is Salviae Miltiorrhizae Radix and its constituents.

1,3,5-Triazine Nitrogen Mustards with Different Peptide Group as Innovative Candidates for AChE and BACE1 Inhibitors.

A series of new analogs of nitrogen mustards (4a–4h) containing the 1,3,5-triazine ring substituted with dipeptide residue were synthesized and evaluated for the inhibition of both acetylcholinesterase (AChE) and β-secretase (BACE1) enzymes. The AChE inhibitory activity studies were carried out using Ellman’s colorimetric method, and the BACE1 inhibitory activity studies were carried out using fluorescence resonance energy transfer (FRET). All compounds displayed considerable AChE and BACE1 inhibition. The most active against both AChE and BACE1 enzymes were compounds A and 4a, with an inhibitory concentration of AChE IC50 = 0.051 µM; 0.055 µM and BACE1 IC50 = 9.00 µM; 11.09 µM, respectively.

Sesquiterpenoids and 2-(2-Phenylethyl)chromone Derivatives from the Resinous Heartwood of Aquilaria sinensis

One novel spirolactone, aquilarisinolide (1), three new sesquiterpenoids, (2R,4S,5R,7R)-2-hydroxyeremophila-9,11-dien-8-one (2), (1R,4S,5S,7R,11R)-13-hydroxyepidaphnauran-9-en-8-one (3), and (4R,5S,7R,8S,10S,13R)-8,13-dihydroxyrotunda-1,11-dien-3-one (4), together with 13 known compounds (5–17) were isolated from the resinous heartwood of Aquilaria sinensis (Thymelaeaceae). The structures of the new compounds were elucidated based on the analysis of NMR and MS data and theoretical calculations their ECD spectra. The isolated compounds were evaluated for their protective activities against PC12 cell injury induced by corticosterone (CORT) and 1-methyl-4-phenylpyridine ion (MPP+), as well as inhibitory activities against BACE1. Compound 4, 5,6-dihydroxy-2-(2-phenylethyl)chromone (5), daphnauranol B (7), 6-methoxy-2-[2-(3-methyoxyphenyl)ethyl]chromone (10), isoagarotetrol (14), and 1-hydroxy-1,5-diphenylpentan-3-one (16) showed significant protective effects on CORT-induced injury in PC12 cells at a concentration of 20 μM (P < 0.001). Isoagarotetrol (14) showed a significant protective effect on MPP+-induced injury in PC12 cells at a concentration of 20 μM (P < 0.001), while compound 4 showed a moderate activity (P < 0.01). The BACE1-inhibitory activities of all tested compounds were very weak with less than 30% inhibition at a concentration of 20 μM.Graphic

Synthesis and evaluation of multi-target-directed ligands with BACE-1 inhibitory and Nrf2 agonist activities as potential agents against Alzheimer's disease.

Cumulative evidence suggests that β-amyloid and oxidative stress are closely related with each other and play key roles in the process of Alzheimer's disease (AD). Multitarget regulation of both pathways might represent a promising therapeutic strategy. Here, a series of selenium-containing compounds based on ebselen and verubecestat were designed and synthesized. Biological evaluation showed that 13f exhibited good BACE-1 inhibitory activity (IC50=1.06 μΜ) and potent GPx-like activity (ν0=183.0μMmin-1). Aβ production experiment indicated that 13f could reduce the secretion of Aβ1-40 in HEK APPswe 293T cells. Moreover, 13f exerted a cytoprotective effect against the H2O2 or 6-OHDA caused cell damage via alleviation of intracellular ROS, mitochondrial dysfunction, Ca2+ overload and cell apoptosis. The mechanism studies indicated that 13f exhibited cytoprotective effect by activating the Keap1-Nrf2-ARE pathway and stimulating downstream anti-oxidant protein including HO-1, NQO1, TrxR1, GCLC, and GCLM. In addition, 13f significantly reduced the production of NO and IL-6 induced by LPS in BV2 cells, which confirmed its anti-inflammatory activity as a Nrf2 activator. The BBB permeation assay predicted that 13f was able to cross the BBB. In summary, 13f might be a promising multi-target-directed ligand for the treatment of AD.

The Effect of Steaming and Fermentation on Nutritive Values, Antioxidant Activities, and Inhibitory Properties of Tea Leaves.

Fermented tea (Cha-miang in Thai) is a local product made by traditional food preservation processes in Northern Thailand that involve steaming fresh tea leaves followed by fermenting in the dark. Information on changes in nutritive values, bioactive compounds, antioxidant activities, and health properties that occur during the steaming and fermenting processes of tea leaves is, however, limited. Changes in nutritive values, phenolics, antioxidant activities, and in vitro health properties through inhibition of key enzymes that control obesity (lipase), diabetes (α-amylase and α-glucosidase), hypertension (angiotensin-converting enzyme (ACE)), and Alzheimer’s disease (cholinesterases (ChEs) and β-secretase (BACE-1)) of fermented tea were compared to the corresponding fresh and steamed tea leaves. Results showed that energy, carbohydrate, and vitamin B1 increased after steaming, while most nutrients including protein, dietary fiber, vitamins (B2, B3, and C), and minerals (Na, K, Ca, Mg, Fe, and Zn) decreased after the steaming process. After fermentation, energy, fat, sodium, potassium, and iron contents increased, while calcium and vitamins (B1, B2, B3, and C) decreased compared to steamed tea leaves. However, the contents of vitamin B1 and iron were insignificantly different between fresh and fermented tea leaves. Five flavonoids (quercetin, kaempferol, cyanidin, myricetin, and apigenin) and three phenolic acids (gallic acid, caffeic acid, and p-coumaric acid) were identified in the tea samples. Total phenolic content (TPC) and antioxidant activities increased significantly after steaming and fermentation, suggesting structural changes in bioactive compounds during these processes. Steamed tea exhibited high inhibition against lipase, α-amylase, and α-glucosidase, while fermented tea possessed high anti-ChE and anti-ACE activities. Fresh tea exhibited high BACE-1 inhibitory activity. Results suggest that tea preparations (steaming and fermentation) play a significant role in the amounts of nutrients and bioactive compounds, which, in turn, affect the in vitro health properties. Knowledge gained from this research will support future investigations on in vivo health properties of fermented tea, as well as promote future food development of fermented tea as a healthy food.

Synthesis and biological evaluation of 2-arylbenzofuran derivatives as potential anti-Alzheimer’s disease agents

Alzheimer's disease (AD) is a type of progressive dementia caused by degeneration of the nervous system. A single target drug usually does not work well. Therefore, multi-target drugs are designed and developed so that one drug can specifically bind to multiple targets to ensure clinical effectiveness and reduce toxicity. We synthesised a series of 2-arylbenzofuran derivatives and evaluated their in vitro activities. 2-Arylbenzofuran compounds have good dual cholinesterase inhibitory activity and β-secretase inhibitory activity. The IC50 value of compound 20 against acetylcholinesterase inhibition (0.086 ± 0.01 µmol·L−1) is similar to donepezil (0.085 ± 0.01 µmol·L−1) and is better than baicalein (0.404 ± 0.04 µmol·L−1). And most of the compounds have good BACE1 inhibitory activity, of which 3 compounds (8, 19 and 20) show better activity than baicalein (0.087 ± 0.03 µmol·L−1). According to experimental results, 2-arylbenzofuran compounds provide an idea for drug design to develop prevention and treatment for AD.

Discovery of Sulforaphane as a Potent BACE1 Inhibitor Based on Kinetics and Computational Studies

BACE1 is the rate-limiting enzyme involved in the production and deposition of β-amyloid (Aβ). Since neurotoxic Aβ plays a critical role in Alzheimer’s disease (AD) pathogenesis, BACE1 has emerged as a key target for preventing AD. In the present study, the potential of sulforaphane, an isothiocyanate found in cruciferous vegetables, as a BACE1 inhibitor has been investigated. Sulforaphane exhibited six times more potent activity against BACE1 compared to well-known positive controls including resveratrol and quercetin. Sulforaphane presented selective and non-competitive BACE1 inhibitory activity with low off-target inhibition of BACE2 and other aspartic and serine proteases. In addition, sulforaphane presented negative binding energy, suggesting that the compound had a high affinity for BACE1. It interacted with locations other than the active binding sites of BACE1 through van der Waals forces. Overall, sulforaphane appeared to be a promising candidate with potent and selective BACE1 inhibitory properties that play an important role in AD prevention.

Synthesis, In Silico and In Vitro Evaluation of Some Flavone Derivatives for Acetylcholinesterase and BACE-1 Inhibitory Activity.

Acetylcholinesterase (AChE) and β-secretase (BACE-1) have become attractive therapeutic targets for Alzheimer’s disease (AD). Flavones are flavonoid derivatives with various bioactive effects, including AChE and BACE-1 inhibition. In the present work, a series of 14 flavone derivatives was synthesized in relatively high yields (35–85%). Six of the synthetic flavones (B4, B5, B6, B8, D6 and D7) had completely new structures. The AChE and BACE-1 inhibitory activities were tested, giving pIC50 3.47–4.59 (AChE) and 4.15–5.80 (BACE-1). Three compounds (B3, D5 and D6) exhibited the highest biological effects on both AChE and BACE-1. A molecular docking investigation was conducted to explain the experimental results. These molecules could be employed for further studies to discover new structures with dual action on both AChE and BACE-1 that could serve as novel therapies for AD.

Synthesis, In Silico and In Vitro Evaluation for Acetylcholinesterase and BACE-1 Inhibitory Activity of Some N-Substituted-4-Phenothiazine-Chalcones.

Acetylcholinesterase (AChE) and beta-secretase (BACE-1) are two attractive targets in the discovery of novel substances that could control multiple aspects of Alzheimer’s disease (AD). Chalcones are the flavonoid derivatives with diverse bioactivities, including AChE and BACE-1 inhibition. In this study, a series of N-substituted-4-phenothiazine-chalcones was synthesized and tested for AChE and BACE-1 inhibitory activities. In silico models, including two-dimensional quantitative structure–activity relationship (2D-QSAR) for AChE and BACE-1 inhibitors, and molecular docking investigation, were developed to elucidate the experimental process. The results indicated that 13 chalcone derivatives were synthesized with relatively high yields (39–81%). The bioactivities of these substances were examined with pIC50 3.73–5.96 (AChE) and 5.20–6.81 (BACE-1). Eleven of synthesized chalcones had completely new structures. Two substances AC4 and AC12 exhibited the highest biological activities on both AChE and BACE-1. These substances could be employed for further researches. In addition to this, the present study results suggested that, by using a combination of two types of predictive models, 2D-QSAR and molecular docking, it was possible to estimate the biological activities of the prepared compounds with relatively high accuracy.

Design of Curcumin and Flavonoid Derivatives with Acetylcholinesterase and Beta-Secretase Inhibitory Activities Using in Silico Approaches.

Acetylcholinesterase (AChE) and beta-secretase (BACE-1) are the two crucial enzymes involved in the pathology of Alzheimer’s disease. The former is responsible for many defects in cholinergic signaling pathway and the latter is the primary enzyme in the biosynthesis of beta-amyloid as the main component of the amyloid plaques. These both abnormalities are found in the brains of Alzheimer’s patients. In this study, in silico models were developed, including 3D-pharmacophore, 2D-QSAR (two-dimensional quantitative structure-activity relationship), and molecular docking, to screen virtually a database of compounds for AChE and BACE-1 inhibitory activities. A combinatorial library containing more than 3 million structures of curcumin and flavonoid derivatives was generated and screened for drug-likeness and enzymatic inhibitory bioactivities against AChE and BACE-1 through the validated in silico models. A total of 47 substances (two curcumins and 45 flavonoids), with remarkable predicted pIC50 values against AChE and BACE-1 ranging from 4.24–5.11 (AChE) and 4.52–10.27 (BACE-1), were designed. The in vitro assays on AChE and BACE-1 were performed and confirmed the in silico results. The study indicated that, by using in silico methods, a series of curcumin and flavonoid structures were generated with promising predicted bioactivities. This would be a helpful foundation for the experimental investigations in the future. Designed compounds which were the most feasible for chemical synthesis could be potential candidates for further research and lead optimization.

Anticholinesterase Activity of Cinnamic Acids Derivatives: In Vitro, In Vivo Biological Evaluation, and Docking Study

Background: Acetylcholine deficiency in the hippocampus and cortex, aggregation of amyloid-beta, and beta-secretase overactivity have been introduced as the main reasons in the formation of Alzheimer’s disease. Objective: A new series of cinnamic derived acids linked to 1-benzyl-1,2,3-triazole moiety were designed, synthesized, and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities. Methods: Colorimetric Ellman’s method was used for the determination of IC50% of AchE and BuChE inhibitory activity. The kinetic studies, neuroprotective activity, BACE1 inhibitory activity, evaluation of inhibitory potency on Aβ1-42 self-aggregation induced by AchE, and docking study were performed for studying the mechanism of action. Results: Some of the synthesized compounds, compound 7b-4 ((E)-3-(3,4-dimethoxyphenyl)-N-((1- (4-fluorobenzyl)-1H-1,2,3-triazole-4-yl) methyl) acrylamide) depicted the most potent acetylcholinesterase inhibitory activities ( IC50 = 5.27 μM ) and compound 7a-1 (N- ( (1- benzyl- 1H- 1, 2, 3- triazole - 4-yl) methyl) cinnamamide) demonstrated the most potent butyrylcholinesterase inhibitory activities (IC50 = 1.75 μM). Compound 7b-4 showed neuroprotective and β-secretase (BACE1) inhibitory activitiy. In vivo studies of compound 7b-4 in Scopolamine-induced dysfunction confirmed memory improvement. Conculusion: It should be noted that molecular modeling (compounds 7b-4 and 7a-1) and kinetic studies (compounds 7a-1 and 7b-4) showed that these synthesis compounds interacted simultaneously with both the catalytic site (CS) and peripheral anionic site (PAS) of AChE and BuChE.

N-Cyclohexylimidazo[1,2-a]pyridine derivatives as multi-target-directed ligands for treatment of Alzheimer's disease

Alzheimer’s disease (AD) is the most common form of dementia. While drugs that target several pathways underlying AD have been proposed, effective treatments remain to be discovered. BACE1, an enzyme associated with AD progression, is a promising target for developing anti-Alzheimer drugs. To find novel multifunctional anti-Alzheimer agents, we designed and synthesized a series of new substituted benzyl-1H-1,2,3-triazol-4-yl-N-cyclohexylimidazo[1,2-a]pyridin-3-amine. The in vitro screening results revealed that most of the compounds exhibited moderate to potent BACE1 and BuChE inhibitory and antioxidant activities. Compounds 7f and 7g, bearing dichloro (2,3-Cl2 and 3,4-Cl2) moieties on the benzyl pendant were selected as the most active compounds in our BACE1 inhibitory assay with respective IC50 values of about 12 and 8.9 μM. In addition, compounds 7g and 7h (4-bromo derivative) showed the highest BuChE inhibitory activity with IC50 of 3.2 and 2.5 µM, respectively. Compound 7g also possessed antioxidant activity with an IC50 value of 10.2 μM and metal chelation potential. Moreover, docking studies were performed to investigate the possible mechanism of inhibition. Taken together, we demonstrate that N-cyclohexylimidazo[1,2-a]pyridine containing triazole motif derivatives deserve further investigation for anti-Alzheimer drug development.

Generative Adversarial Networks (GANs) Based Synthetic Sampling for Predictive Modeling.

In the present report we evaluate the possible utility of the Generative Adversarial Networks (GANs) in mapping the chemical structural space for molecular property profiles, with the goal of subsequently yielding synthetic (artificial) samples for ligand-based molecular modeling. Two case studies are considered: BACE-1 (β-Secretase 1) and DENV (Dengue Virus) inhibitory activities, with the former focused on data populating and the latter on data balancing tasks. We train GANs using subsamples extracted from datasets for each bioactivity endpoint, and apply the trained networks in generating synthetic examples from the respective bioactivity chemical spaces. Original and synthetic samples are pooled together and employed to build BACE-1 and DENV inhibitory activity classifiers and their performance evaluated over tenfold external validation sets. In both case studies, the obtained classifiers demonstrate satisfactory predictivity with the former yielding accuracy (ACC) and Mathew's correlation coefficient (MCC) values of 0.80 and 0.59, while the latter produces balanced accuracy(BACC) and MCC values of 0.81 and 0.70, respectively. Moreover, the statistics of these classifiers are compared with those of other models in the literature demonstrating comparable to better performance. These results suggest that GANs may be useful in mapping the chemical space for molecular property profiles of interest, and thus allow for the extraction of synthetic examples for computational modeling.

Design and Synthesis of Novel Arylisoxazole-Chromenone Carboxamides: Investigation of Biological Activities Associated with Alzheimer's Disease.

A novel series of hybrid arylisoxazole-chromenone carboxamides were designed, synthesized, and evaluated for their cholinesterase (ChE) inhibitory activity based on the modified Ellman's method. Among synthesized compounds, 5-(3-nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide depicted the most acetylcholinesterase (AChE) inhibitory activity (IC50 =1.23 μm) and 5-(3-chlorophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide was found to be the most potent butyrylcholinesterase (BChE) inhibitor (IC50 =9.71 μm). 5-(3-Nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide was further investigated for its BACE1 inhibitory activity as well as neuroprotectivity and metal chelating ability as important factors involved in onset and progress of Alzheimer's disease. It could inhibit BACE1 by 48.46 % at 50 μm. It also showed 6.4 % protection at 25 μm and satisfactory chelating ability toward Zn2+ , Fe2+ , and Cu2+ ions. Docking studies of 5-(3-nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide and 5-(3-chlorophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide confirmed desired interactions with those amino acid residues of the AChE and BChE, respectively.

Icaritin, an inhibitor of beta-site amyloid cleaving enzyme-1, inhibits secretion of amyloid precursor protein in APP-PS1-HEK293 cells by impeding the amyloidogenic pathway.

BackgroundIcaritin (ICT) is a prenylflavonoid derivative from Epimedium brevicornum Maxim. ICT has been shown to have neuroprotective effects. We investigate how ICT affects secretion of amyloid precursor protein (APP).MethodsWe exposed APP-PS1-HEK293 cells to ICT to investigate its effect on beta-site amyloid cleaving enzyme (BACE)1. Cell viability was evaluated by MTT and lactate dehydrogenase (LDH) assays. The half-maximal inhibitory concentration (IC50) of ICT for BACE1 was measured using fluorescence resonance energy transfer. Effects of ICT on the mRNA expression of APP were assessed by quantitative polymerase chain reaction, and protein expression was measured by western blotting and immunofluorescence.ResultsIcaritin inhibited BACE1 activity and IC50 was 5.70 ± 1.09 μM. Compared with the control group, at ICT concentrations of 5 μM and 10 μM, the viability increased and LDH leakage decreased in APP-PS1-293 cells. Also, mRNA expression of A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) increased, while that of BACE1 and presenilin-1 (PS1) decreased, upon ICT treatment. Western blotting and immunofluorescence confirmed that protein expression of ADAM10, BACE1 and PS1 showed the same trend. Expression of the APP fragments sAPPβ and C-terminal fragment β decreased, while that of sAPPα increased, upon ICT treatment. Expression of amyloid β peptides in APP-PS1-HEK293 cells was lower in ICT-treated groups compared with that in the control group.ConclusionsIcaritin, as a BACE1 inhibitor, inhibits APP secretion in APP-PS1-HEK293 cells by impeding the amyloidogenic pathway.

The Investigation on Cholinesterases and BACE1 Inhibitory Activities in Various Tea Infusions

Alzheimer’s disease (AD) is a chronic neurological disease related to the decline in brain and nervous system functions. At present, inhibitions of cholinesterases (ChEs) including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) to enhance neurotransmitters and retardation of b-amyloid formation through b-secretase (BACE1) inhibition are 2 hypotheses for AD prevention and treatment. Hence, this study aims to investigate inhibitory activities against ChEs of various tea varieties of Camellia sinensis and herbal teas. At this step, the screening methodology for ChEs inhibitory activities in various tea varieties in order to provide a fast, inexpensive and convenient method for the detection of anti-cholinesterase activity was optimized. Then, selected tea with high ChEs was further examined regarding its BACE1 activity. As results, all tea samples displayed both anti-AChE and -BChE activities with the broad ranges of 6 - 85 % and 0 - 72 % inhibitory activities, respectively. Interestingly, C. sinensis teas exhibited higher ChEs inhibitory activities than herbal teas, in exception of Pandanus amaryllifolius (pandan) tea, which exhibited comparable inhibitory activities as C. sinensis teas. Pandan leaves were found to exhibit anti-BACE1 activity with 98 % inhibition. Besides, preliminary in vivo study showed that pandan leaves extract was able to rescue climbing defect observed in AD Drosophila melanogaster model, indicating the potential roles of pandan leaves in AD prevention.

Influence of functional moiety in lupane-type triterpenoids in BACE1 inhibition

Lupane-type triterpenoids have shown a potential effect against neurodegenerative disorders. Alzheimer’s disease, one of the common neurodegenerative disease, is evident by the accumulation of amyloid-beta (Aβ) plaque in the extracellular regions of the brain. β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is a key enzyme for the Aβ formation viathe cleavage of amyloid precursor protein (APP). Therefore, to find the potent BACE1 inhibitors and furthermore to explore the role of the functional group responsible for the strong BACE1 inhibitory activity, we synthesized a series of triterpenoids with lupane skeleton starting from the natural compounds calenduladiol and lupeol. Compound 1 revealed a potent competitive BACE1 inhibitory activity (IC50 = 16.77 ± 1.16 μM; Ki = 19.38). Furthermore, the molecular docking simulation revealed the importance of Tyr198 residue along with the other hydrophobic interactions for the strong affinity of 1‒BACE1 complex. To sum up, our results demonstrated the importance of carbonyl moiety at 3 and 16 position of lupane-type triterpenoid over the hydroxyl group at the same position.

Potential anti-Alzheimer effects of selected Lamiaceae plants through polypharmacology on glycogen synthase kinase-3β, β-secretase, and casein kinase 1δ

The aerial parts of Lamiaceae plants have been used since ancient times all over the world, especially in Mediterranean cultures, for their medicinal and culinary properties. Although some of them have a historical role in the improvement of cognition and memory, the precise mechanism of these plants remains unclear.This study evaluated the potential anti-Alzheimer effects of some popular cultivated Lamiaceae plants via their inhibitory potential towards glycogen synthase kinase (GSK-3β), β-secretase (BACE-1), and casein kinase 1δ (CK-1δ), enzymes related to AD.Luminometric-based assays were used for the evaluation of GSK-3β and CK-1δ inhibitory activities in which a fluorescence resonance energy transfer (FRET) assay was used for determining BACE-1 inhibitory activity. The major compounds were identified by high pressure liquid chromatography with diode array detection coupled with electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS).Among the extracts tested, Origanum onites L., O. majorana L., and Mentha piperita L. were the most active ones for GSK-3β inhibitory activity, with IC50 values under 15 μg/mL, while O. majorana and S. officinalis L. were the most active for BACE-1 and O. onites, O. majorana, and Melissa officinalis L. for CK-1δ, with half maximal inhibitory concentration (IC50) values under 250 μg/mL. On the basis of the composition of these active extracts it is apparent that flavonoids, i.e. apigenin, luteolin, and their glycoside derivatives, along with phenolic acids, i.e. rosmarinic acid and salvianolic acids, are the major principles of these active extracts.The outcomes of this study supported the traditional use of Lamiaceae plants for cognitive disorders and highlighted their underlying mechanisms, targeting GSK-3β/BACE-1/CK-1δ together for the first time.

4-Substituted 2-amino-3,4-dihydroquinazolines with a 3-hairpin turn side chain as novel inhibitors of BACE-1

Herein, we report the identification, design, and synthesis of a series of 4-substituted 2-amino-3,4-dihydroquinazolines with hairpin turn side chains as novel inhibitors of BACE-1. The dihydroquinazoline derivatives were rationally designed by modifying the amide group and relocating the α -hydrophobic substituent on the hairpin turn side chain of lead compound 2 to the C4-position on the 3,4-dihydroquinazoline scaffold to facilitate interactions with the S1, S2 and S1′ subsites of BACE-1. Among these derivatives, two compounds exhibited potent BACE-1 inhibitory activity: 4-methyl-substituted (22a, BACE-1 CFA IC50 = 0.38 μM; BACE-1 WCA IC50 = 0.14 μM) and 4-cyclohexylmethyl-substituted (22b, BACE-1 CFA IC50 = 0.49 μM; BACE-1 WCA IC50 = 0.14 μM) 2-amino-3,4-dihydroquinazoline, each bearing a side chain of N-cyclohexyl-N-((1-methyl-1H-pyrazol-4-yl)methyl amide. The results suggest that the structural modifications maintain the hairpin turn topology similar to that of compound 2 and provide an additional interaction with the S2 subsite.

Meroterpenoids with BACE1 Inhibitory Activity from the Fruiting Body of Boletinus asiaticus

BACE1 inhibitory activity-guided fractionation of an extract of the fruiting body of Boletinus asiaticus yielded five novel meroterpenoids (1-5) and one known compound (6; asiaticusin A). The structures of these compounds were determined by interpretation of NMR, MS, and IR spectral data. The five new compounds contain 4-hydroxybenzoic acid and geranylgeranoic acid units. Compounds 4-6 possessed BACE1 inhibitory activity (IC50 values: 14.7, 11.4, and 2.0 μM, respectively).